US whistle-blower Edward Snowden yesterday emerged from hiding in Hong Kong and revealed to the South China Morning Post that he will stay in the city to fight likely attempts by his government to have him extradited for leaking state secrets.

In an exclusive interview carried out from a secret location in the city, the former Central Intelligence Agency analyst also made explosive claims that the US government had been hacking into computers in Hong Kong and on the mainland for years.

At Snowden’s request we cannot divulge details about how the interview was conducted.

A week since revelations that the US has been secretly collecting phone and online data of its citizens, he said he will stay in the city “until I am asked to leave”, adding: “I have had many opportunities to flee HK, but I would rather stay and fight the US government in the courts, because I have faith in HK’s rule of law.”

In a frank hour-long interview, the 29-year-old, who US authorities have confirmed is now the subject of a criminal case, said he was neither a hero nor a traitor and that:

US National Security Agency’s controversial Prism programme extends to people and institutions in Hong Kong and mainland China;

The US is exerting “bullying’’ diplomatic pressure on Hong Kong to extradite him;

Hong Kong’s rule of law will protect him from the US;

He is in constant fear for his own safety and that of his family.

Snowden has been in Hong Kong since May 20 when he fled his home in Hawaii to take refuge here, a move which has been questioned by many who believe the city cannot protect him.

“People who think I made a mistake in picking HK as a location misunderstand my intentions. I am not here to hide from justice, I am here to reveal criminality,” he said.

Snowden said that according to unverified documents seen by the Post, the NSA had been hacking computers in Hong Kong and on the mainland since 2009. None of the documents revealed any information about Chinese military systems, he said.

I’m neither traitor nor hero. I’m an American

One of the targets in the SAR, according to Snowden, was Chinese University and public officials, businesses and students in the city. The documents also point to hacking activity by the NSA against mainland targets.

Snowden believed there had been more than 61,000 NSA hacking operations globally, with hundreds of targets in Hong Kong and on the mainland.

“We hack network backbones – like huge internet routers, basically – that give us access to the communications of hundreds of thousands of computers without having to hack every single one,” he said.

“Last week the American government happily operated in the shadows with no respect for the consent of the governed, but no longer. Every level of society is demanding accountability and oversight.”

Snowden said he was releasing the information to demonstrate “the hypocrisy of the US government when it claims that it does not target civilian infrastructure, unlike its adversaries”.

“Not only does it do so, but it is so afraid of this being known that it is willing to use any means, such as diplomatic intimidation, to prevent this information from becoming public.”

Since the shocking revelations a week ago, Snowden has been vilified as a defector but also hailed by supporters such as WikiLeaks’ Julian Assange.

“I’m neither traitor nor hero. I’m an American,” he said, adding that he was proud to be an American. “I believe in freedom of expression. I acted in good faith but it is only right that the public form its own opinion.”

Snowden said he had not contacted his family and feared for their safety as well as his own.

“I will never feel safe.

“Things are very difficult for me in all terms, but speaking truth to power is never without risk,” he said. “It has been difficult, but I have been glad to see the global public speak out against these sorts of systemic violations of privacy.

“All I can do is rely on my training and hope that world governments will refuse to be bullied by the United States into persecuting people seeking political refuge.”

Asked if he had been offered asylum by the Russian government, he said: “My only comment is that I am glad there are governments that refuse to be intimidated by great power”.

The interview comes on the same day NSA chief General Keith Alexander appeared before Congress to defend his agency over the leaks. It was his first appearance since the explosive revelations were made last week. Alexander’s prepared remarks did not specifically address revelations about the Prism program.

Snowden's revelations threaten to test new attempts to build US-Sino bridges after a weekend summit in California between the nations' presidents, Barack Obama and Xi Jinping.

If true, Snowden's allegations lend credence to China's longstanding position that it is as much a victim of hacking as a perpetrator, after Obama pressed Xi to rein in cyber-espionage by the Chinese military.

Tens of thousands of Snowden’s supporters have signed a petition calling for his pardon in the United States while many have donated money to a fund to help him.

“I’m very grateful for the support of the public,” he said. “But I ask that they act in their interest – save their money for letters to the government that breaks the law and claims it noble.

“The reality is that I have acted at great personal risk to help the public of the world, regardless of whether that public is American, European, or Asian.”

The US consulate in Hong Kong could not be contacted yesterday on a public holiday.